Unloader mechanism



R. CONRADER UNLOADER MECHANISM Filed Dec. 1, wl

3 Sheets-Shaft l v IN\\- Oct. 13, 1925. 1,557,426

R. CONRADER UNLOADER MEGHANISM .e l W oct. 13, 1925. 1,557,426

R; CONRADER UNLOADER MECHANISM Filed Deo. l, 1921 3 Sheets-Sheet 5 Patented Oct. 13, 1925.`

UNITED STATI-:s

PATENT OFFICE.'

Application med December 1, 1921. Serial 11b. 518,164.

To all whom t comm.'

Be it known that I, RUDOLPH Commons, a citizen of the XUnited States, residing at Erie, in the county of Erie and State of Pennsylvania, have invented new and useful Improvements in Unloader Mechanism, of which the following is a specification.

-This invention is designed for use as an unloader for pumps and compressors and is particularly applicable for operation on the discharge of said pumps or compressors. Heretofore unloaders operating on the discharge have usually required a non-return check valve which check valve is subjected to some pressure, or tendency to return to closed position and this pressure, or tendency, has added to the resistance of the discharge of the compressor or pump and thls t pe of unloader hasvhad this disadvantage.

ne of the objects of this invention is to` obviate resistance to the discharge of fluid by reason of the return valve. A further object of the invention is to provide a simple unloader, one of the features of the unloa er being that it comprises an actuatin plunger and the unloading action takes the exhaust of pressure from the plunger rather than the application of pressure to the plunger, thus making a more simple and eiioientmechanism possible. Other details of the inventionwill appear from the specification and claims.

The invention is illustrated in the accompanying drawings as follows Fig. 1 shows 'a central section through the unloader.

Fig. 2 a section on the line 2 2 in Fig. 1.

Fig. 3 a section on the line 3-3 in Fig. 1.

Fig. 4 an end view of the unloader.

Fig. 5 a central section through the unloader with the pilot valve attached.

Fig. 6 a side elevation of a ump or compressor with the -unloader in p ace. FFig. 7 is a section one the line 7 7 in lgmarks the body of the unloader, 2" the y inlet of the unloader, 3 the discharge from the unloader, 4 adischarge from the pump leading tothe inlet 2 of the unloader, 5 a discharge pipe leading from the discharge 3, this pipe leading as desired to a receiver or rece tacle, 6 a pump cylinder 7 a crank shaft dli'iving the pump, 8 a pulley drivin the crank shaft, and l9 a motor from whic the pulley 8 is driven. The body has the "inl'etchamber 10, the 4discharge chamber 11 p ace with,

and the unloader chamber 12, the chamber 10 being between the chambers 11 and 12. A discharge passage 13 leads from the chamber 10 to the chamber 11. It is surrounded by a. seat 14. A passa e 15 connects the inlet chamber 10 with t e unloader chamber 12, this passage being surrounded by a valve seat 16. A valve 17 acts on the seat 14 and is carried by a stem 18. The stem has an extension 19 which operates in a guide 20,`

the guide havin the openings 21 to permit the balancing o pressure on the stem. The stem extends into a controlled chamber 23 which is subjected to receiver or pump discharge pressure when the pump is pumping. Therefore the pressure on the stem 18 1s practically balanced and the pressure on the valve 17 is practically balanced so that during the pumping action the valve 17 moves to an open position and stays there, thus oil'erin no resistance to the discharge of fluid rom the pump. When pressure is discharged from the control chamber 23 as the pressure decreases the pressure 'on the stem 18 becomes unbalanced and immediately this unbalanced condition yieldin ly closes the valve 17 and it operates in t 1s condition in the vslight interval until the unloader operates as hereinafter described.

12. It 1s connected by a passage 25 with the chamber 23 so that the cylinder 24 and the chamber 23 operate as one chamber. plunger 26 operates in the c linder 24. It carries a valve 27 which is la apted to operate on the seat 16 to form a closure between the inlet chamber and the unloader chamber. The plunger also has a gland 28 `making a sliding closure on the stem 18.

The operation of the unloader is as follows: The control chamber 23 is subjected to variations of pressure which pressure is controlled by the pump pressure. When the pressure rises above the desired maximum the pressure in the control chamber is exhausted and when this decrease in pressure has reached a point where the difference in area between the piston 26 and the seat y16 is compensated for any difference in pressure the piston moves opening the valve 27 and allowing the pumped lluid to pass to the unloader chamber 12 and from thence to the atmosphere o r by of the pipe as 12Il to the. inlet of the pump.

The valve 17 is closed under these circumstances as above described. When the pump wayl A cylmder 24 projects into the chamber l pressure reduces, the pressure is again exerted in the chamber 23 and this operating on the piston 26 closes the valve 27 and immediately the valve 17 opens and the pressure on the chamber 23 and the discharge chamber practically balance so that the valve' to close the valve 27 but I prefer to provide a spr'ing 29 which is a very slight spring, simply sufficient to close the valve 2 and hold it closed during an initial stage of the pumping action.

Any desirable pilot valve may be used for controlling the pressure in the control chamber but I have shown a pilot valve Which forms the subject matter of a companion application, pressure controlled valve mechanism, filed Dec. 1, 1921, Serial Number 519,163. .This comprises a valve body 30 having a control passage 31, and inlet and discharge passages 32 and 33 respectively ivith Which the ports 34 and 35 connect the control passages. Valves 36 and 37 control the ports 34 and 35. Stems 38 and 39 extend from the valves to cross heads 40. Springs 41 extend from the notched ends 42 of the cross heads to the ears 43 on the body and tend to maintain the valves in closed position. Projections 44 extend from the yoke 45 in position to engage the cross heads 40. The yoke slides in guides 46. The yoke has an opening 47 into which one arm of a bell crank lever 48 extends. The lever is pivoted on a pin 49 and is connected by a link 50 With a lever 51. The lever is mounted on a pin 52. A diaphragm plate 55 is secured to the valve body and a diaphragm 54 is secured'on the plate by a cover plate 53. The diaphragm plate has a passage 56 connecting With the inlet passage 32, the inlet passage being connected With the discharge, as for instance, the pipe 5, by means of a pipe 32a. A similar passage 56a connects with the passage 33', this being closed by a plug 56", the purpose of this passage in the relief device being of utility to reverse the action of the pilot valve if desired. The diaphragm has a bearing point 57 which extends into a bearing detent 58 in the lever. A screw-threaded extension 60 is arranged on the cover plate 53 and a follower 61 is secured in the extension 60. A counterpressure spring 62 is compressed by the follower and operates on a base plate 63 having a bearing point 64 extending into a detent in the lever 51.

The operation of the pilot' valve is as follows: When the pressure reaches a point this operating `through the link and bell crank operates on the yoke, closing the valve 36 and opening the valve 37, thus exhausting the pressure from the chamber 23. As the pressure decreases and the diaphragm recedes under the influence of the spring the movement of the valve is reversed, closing the valve 37 and opening the valve 36 and again putting pressure on the chamber 23'and insuring the closing of the valve 27.

In order to prevent frequent reversals and what is sometimes termed chattering I prefer to provide a cam 65 on the end of the lever 51 which cam is engaged by a cam 66 on a lever 66a. The lever 66a'is pivoted on a pin 67 extending from the diaphragm plate. A screw 68 extends from the cover plate through the lever 66a. A spring 69 is arranged around the screw and a nut 70 provided by means of Which the pressure on the spring may be varied. It Will be noted with this device as the cams pass the center they Will assist a further movement in the direction of the then movement of the lever but on a reversal they will resist such movement, thus in elect varying the effective action of the counter-pressure device. By adjusting the nut 7 0 and varying the force of the spring 69 this action may be modified as desired.

What I claim as new is z- 1. In an unloader mechanism, the combination of a pump discharge passage; an unloader responsive to pump pressures acting on said passage; a valve preventing a return flow through said discharge passage When the unloader is in unloading position, said valve having a tendency to close; and means subjected to balancing fluid pressure neutralizing said tendency of the valve When the unloader is not unloading.

2. In an unloader mechanism, the combination of a pump discharge passageyan unloader responsive to pump pressures .acte ing on said passage; a' valve preventing a return flow through said discharge passage when the unloader is in unloading position, said valve having a tendency to close; and means balancing the pressure of said valve when the unloader is not unloading and exerting closing pressure on the valve when the unloader is in unloading position.

3. In an unloader mechanism, the combination of a pump discharge passage; an unloader responsive to pump pressures acting on said passage; a valve preventing a return flow through said discharge passage when the unloader is in unloading position, said valve having a tendency to close; and means exerting closing pressure on the valve When the unloader operates, said means `re-` 4. In an unloader mechanism, the combination of a pump discharge passage; an unloader responsive to pumpy pressures acting on said passage; a valve preventing a return flow through the passage when the un-. loader is in unloaded position; and a pressure device. eating on the valve, said device being neutralized with the unloader out of action and exerting closing pressure on the position.

5. In an unloader mechanism, the combination of a pump discharge passage; a pilot valve controlled by the pump pressure; an unloader acting on said passage and controlled by pressure controlled by the pilot valve; a non-return valve preventing a. return flow through the passage when the unloader is acting; and a pressure device subjected to fluid pressure acting on said nonreturn valve tending to open the same and controlled by said pilot valve. j

6. In an unloader mechanism, the combination of a pump discharge passage; a pilot `,valve when the unloader is in unloading Yvalve controlled by the pump pressure; an

unloader acting on said passage'and coni trolled by the .pilot valve, said unloader unloading as it is relieved of pressure by the pilot valve; a non-return valve preventing a return flow through the passage when the unloader is acting; and a pressure device acting on said non-return valve and con-v trolled by said pilot valve.

7. lln an unloader mechanism, the combination of a pump discharge passage; a pilot valve controlled by the pump pressure; an unloader acting on said passage and controlled by pressure controlled by the pilot valve comprising a non-return valve pre-V venting a return dow through the passage when the unloader is acting; and a pressure device' acting on said non-return valve and havin one sidev subjected to pressure controlle by said pilot valve and its opposite side to discharge passage pressure, said pressure device being made active by discharge passage pressure through the relief of pressure from the unloader by the pilot valve.

8. lfnan unloader mechanism, the combination of a body having an inlet chamber adapted to receive the discharge of a pump; a discharge chamber; an unloader chamber; a control chamber; a discharge passage between the inlet chamber and the discharge chamber; an unloader passage between the inlet chamber and the unloader chamber; an unloader valve controlling the unloader passage; a plunger in the controlling chamber controlling the unloader valve; a discharge valve controlling the discharge passage ;-and a pressure device controlling the discharge valve having one side subjected to pressure opposite side discharge side of the disinlet chamber and the unloader chamber; an

unloader valve contro-lling the unloader passage; a plunger in the controlling chamber controlling the unloader valve; a discharge valve controlling the discharge passage; 'and a pressure device controlling 'the discharge valve in the form or a stem,- for said valve, said stem extending into the control chamber and having one end subjected to the pressure of the control chamber and the opposite end to the pressure in the discharge passage at the discharge side ol the dis` charge valve.

l0. lln an unloader mechanism, the combination ol a body having an inlet chamber adapted to receive the discharge of a pump; t

a discharge chamber; an unloader chamber; a control chamber; a discharge passa e between the inlet chamber and the disc arge chamber; an unloader passage between the inlet chamber and the unloader chamber; an

unloader valve controlling the unloader passage; a plunger in the controlling chamberl controlling the unloader valve; a dischar e valve controlling the discharge passage, said unloader valve and discharge Valve being in axial alinement; and a pressure controlling the discharge valve having one side subjected to pressure in the .control device chamber and the opposite side to pressure at .the discharge side of the discharge valve.

lln testimony whereof I have hereunto set m hand.

y RUDOLPH CONRADER, 

